Tommy never put in the work? He showed up to the hospital to be there for Madney's wedding despite the fact he was just getting off a long shift and fighting a huge fire, showed up at the hospital when buck dislocated his shoulder and took care of him - bringing him meds, fluffing his pillow, (also sleeping on a couch so he could be close by), making him breakfast in the morning. He dressed up in a full suit and went to a cemetery with Buck as he gave a ghost a funeral to "break a curse," got up early went to the store and made him a whole meal before buck even woke up. I don't think it's fair to pretend he doesn't put work into the relationship.
it's not like I think he never did anything nice (if that were true I imagine the relationship would've been much shorter lmao), it's just that in most of these situations he either quits when it looks like he'll have to start working for it (the break up), never puts in the effort at all (no costume for the bachelor party, somehow never learned that buck hates basketball?), or kind of half asses it and gets outdone by eddie anyway (the halloween ep). and then like I said, in this last ep he's only shown to be interested again once he learns that eddie's moved away, and is essentially love bombing buck to try and rekindle their relationship because now he thinks it's gonna be easy with eddie out of the picture. which is like. clearly he's decided that he could never compete with eddie if he were around, but he also just doesn't care enough about his relationship with buck to try.
